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To ALL WHoM 1T MAY ooNcERN.

vBe it known that I, WARREN P. MILLER, of the city, county, and State of New York, haveA invented a new and useful Improvement in Grindstones; and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable others skilled in the art to make andusethe same, reference being had to the accompanying drawings forming part of this specification, in which- Figure l. represents a plan or top view of my improved grin dstone.

Figure 2 is a central sectional view ofthe same. I

Figure 3 is a detail sectional view of the same, the plane of section being indicated by the line :2: a', g. I.

Similar letters of reference indicate corresponding parts.

This invention relates to a grindstone which is composed of a number of blocks of grinding material, which are placed and held upon a cast-iron or other metal disk in'` vsuch a manner that they form a ring of grindingv material, the face, and not the periphery, of which is to be used for grinding saws and other metal articles.

The invention consists in the use of a metal disk, which is mounted upon a shaft in any desirable manner, and around the circumference of which a. ange'is formed, which projectsfrom one face of the disk, and which serves to hold the blocks of stone or other grinding material that are placed upon the face of the disk, and that are held in place by means of keys fitted through holes linthe disk. The blocks are thus held between the aforesaid flange and the keys, and form a ring of grinding material, one face of which may be used for grinding purposes. Between the blocks or otherwise in the grinding material are arranged grooves which are radiant from the centre of the disk. These grooves are for the purpose of receiving the dust and lchaii', whichwill then be thrown out by centrifugal force, while without the grooves the grinding surface would soon be clogged, and the operationof grinding delayed.

A represents a disk, made of cast iron, or other suitable material, having a ange, a, around its circumference. B B are blocks of grinding material, which arelaid against this ange, and held between the same, and keys G C, which are. fitted through slots in the disk, and which are held in position by wedges b In, as is clearly shown iug. 2. It will be observed that the inner-edge of the ange a is inclined, and also that odgeiof the keys C which comes in contact with the stones B. The latter are therefore dove-tailed between the flange and keys, as is clearly shown in fig. 2, and are thus irm'ly held inposition. These sides-of the blocks B which are at right angles with the flange are bevelled off towards the face of the stone', in curved lines, so that grooves d d are formed between every two adjoining stones, as shown in fig. 3. For grinding circular and other saws, Iprefer to arrange two such grinding-stones, one being mounted on a shaft, D, while the other turns loose thereon. The stones are then revolved in' opposite directions, and the saw E placed between them as is indi cated in g. 2. The grinding faces are arranged the required distance apart, and the direction of the stones can be reversed whenever desired.

It is evident that this mode of constructing grindstones is far cheaper than the stones now used. I can make use of the old refuse stones, and shape the same into blocks to fit the disk A, and these blocks can then be ground olf to the height of the fiange a. When one set of stones is used up, it is removed from the disk and another set inserted in its place, the disk not being affected by the wear of the grinding material. Ineqiralities in the grinding surface can be much easier corrected in this Astone than onith'e periphery of the usual grind'- ,stont-is. The grooves d d can be out into the solid grinding material, instead of being formed'at the joints of" the blocks, or in addition to the latter, as shown at d?, iig. 3.

Having thus described my invention, I claim as new, and desire to secure by Letters Patent- I. The mode of securing the blocks B tothe disk A, by means of the fiange a and keys C, all made and operating substantially as herein shown and described.

2. The grooves d dv', when arranged in the grinding surface, substantially in the manner and for the purpose herein shown and described.

i 3. Constructing grindstones by combining the shaft D, and the'disk A, with the stones B, keys C, all made and operating substantially as and for the purpose hereing shown and described.

y I WARREN P. MILLER.

Witnesses:I

WM. F. McNAMARA, ALEX. F. Renners. 

